Implement global circular reference handler in line with latest symfony practices and remove now redundant code from current normalizers

config/packages/serializer.yaml

@@ -0,0 +1,4 @@
+framework:
+    serializer:
+        enabled: true
+        enable_attributes: true

config/services.yaml

@@ -18,3 +18,8 @@ services:
     Chill\MainBundle\ArgumentResolver\EntityValueResolver:
         tags:
             - { name: controller.argument_value_resolver, priority: 50 }
+
+    Chill\MainBundle\Serializer\CircularReferenceHandler:
+        public: false
+        tags:
+            - { name: 'serializer.circular_reference_handler' }